Welcome to Physics 43!

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1 Welcome to Physics 43!

2 Classical Mechanics! Study of the motion of objects and mechanical systems that are large relative to atoms and move at speeds much slower than the speed of light.

3 You can t get to Modern Physics without doing Classical Physics! The fundamental laws and principles of Classical Physics are the basis Modern Physics.

4 Cosmic Quest(ions) What is the Universe? How did it come into existence? What is Consciousness? What is the fate of the Universe? Is there a theory of everything?

5 Some Physical Models of the Universe A Brief History of Physics

6 Physics seeks a single theory of Everything.and it always has Bubble Universes Superstrings Theory of Everything (TOE)

7 History is IMPORTANT The historical development of science shows us the process of discovery and the way our brains work and POSSIBLY the inherent biases and limitations of the rational mind. By studying the historical development of science we learn about the mistakes that have been made so hopefully we do not repeat them...and maybe we discover old ideas that still have something to teach us about the way the universe works or at least, how our brains work

9 Let no one unversed in geometry enter here. The Universe is made of pure mathematical ideas the Platonic Solids. Plato believed that the stars, planets, Sun and Moon move round the Earth in crystalline spheres.

Earth and the universe were seen as constructed

indestructible substance called ether (aether) and

10 Earth and the universe were seen as constructed out of five basic elements: earth, water, air, fire, and ether. The natural place of the motionless Earth was at the center of that universe. The stars in the heavens were made up of an indestructible substance called ether (aether) and were considered as eternal and unchanging. The laws of nature of the Earth were different from those of the Heavens.

11 Modern Reductionism!

12 The Sun and the planets would revolve in small circles whose centers revolve in large circles about the Earth ("epicycles") which is at rest and at the center of the Universe.

13 From our perspective, the sun and stars appear to orbit us!

14 Ptolemy's geocentric system, adopted by the Roman Catholic Church, dominated western thought until the time of Copernicus, 14 centuries later..

15 5 th -15 th Centuries

19 Developed science & medicine based on observation and experiment, rather than on conjecture creating the basis of what would later be called The Scientific Method.

21 European Enlightenment Renaissance 14 th & 15 th Century The Vitruvian Man 1490

Like Aristotle and Ptolemy, Copernicus retained the conventional idea that the

22 Copernicus put the Sun at the center of the solar system with the Earth orbiting around the Sun, thus proposing a heliocentric cosmology. Like Aristotle and Ptolemy, Copernicus retained the conventional idea that the planets moved in perfectly circular orbits and continued to believe that the stars were fixed and unchanging.

23 REVOLUTION!

24 The Rejection of the Copernican Heliocentric Model

25 I hold that the Sun is located at the centre of the revolutions of the heavenly orbs and does not change place, and that the Earth rotates on itself and moves around it.

26 Galileo Challenged The Dogma Of Natural Motion with Experiments

27 Heliocentric Heretics

28 Rome, Campo de'fiori: The monument to Giordano Bruno, burnt at the stake here.

29 The Trial of Galileo June 22, 1633: Galileo was convicted and sentenced to life imprisonment by the Catholic Inquisition. In 1992, the church finally lifted its edict of Inquisition against Galileo, who went to his grave a devout Catholic, despite the church s treatment of him.

30 Based on observational data he derived three laws of planetary motion that put the sun at he center of the universe with elliptical orbits.

31 Kepler s 3 Laws of Planetary Motion 1: The orbit of each planet about the sun is an ellipse with the sun at one focus. 2. Each planet moves so that it sweeps out equal areas in equal times. 3. The square of the orbital period of any planet is proportional to the cube of the semimajor axis of the elliptical orbit. T r = constant

32 Planet Orbits are Elliptical

33 "The next question was - what makes planets go around the sun? At the time of Kepler some people answered this problem by saying that there were angels behind them beating their wings and pushing the planets around an orbit. As you will see, the answer is not very far from the truth. The only difference is that the angels sit in a different direction and their wings push inward." -Richard Feynman

Isaac Newton (1642-1727) Using his Calculus, Newton derives Kepler s

Universal Law of Gravity. Newton is the man of the millennium.

34 Isaac Newton ( ) Using his Calculus, Newton derives Kepler s three laws of planetary motion from his own three laws of motion and his Universal Law of Gravity. Newton is the man of the millennium. In Principia (1687 ) Newton Invented Calculus 3 Laws of Motion Universal Law of Gravity

35 Newton s First Law (Law of Inertia) An object will remain at rest or in a constant state of motion unless acted upon by external net forces.

36 Newton s 2nd Law F = ma a = F net m The acceleration of object is directly related to the net forces acting on it and inversely proportional to its mass.

37 Newton s 3rd Law F hand on wall = F wall on hand To every force there is an equal but opposite reaction force.

38 Universal Law of Gravity 1687 Every particle in the Universe attracts every other particle with a force along a line joining them. The force is directly proportional to the product to their masses and inversely proportional to the square of the distance between them. d M m F ~ mm d 2

Vis Viva: Kinetic Energy Conservation of Energy Proposed by Gottfried Leibniz over the period 1676 1689, the theory was controversial as it seemed to

39 Vis Viva: Kinetic Energy Conservation of Energy Proposed by Gottfried Leibniz over the period , the theory was controversial as it seemed to oppose the theory of conservation of momentum advocated by Sir Isaac Newton and René Descartes. The two theories are now understood to be complementary.

The total amount of energy in the Universe is constant and can never change.

40 Conservation of Energy Energy can neither be created nor destroyed. It may change in form or be transferred from one system to another. The total amount of energy in the Universe is constant and can never change. E i = E f Except for VERY brief amounts of time according to the Heisenberg Uncertainty Principle.

Robert Hooke (1635-1703) Leading figure in Scientific Revolution Contemporary and arch enemy of Newton Hooke s Law

41 Robert Hooke ( ) Leading figure in Scientific Revolution Contemporary and arch enemy of Newton Hooke s Law of elasticity Worked in Physics, Biology, Meteorology, Paleontology Devised compound microscope Coined the term cell

42 1800 s: Atomic Emission of Light Each chemical element produces its own unique set of spectral lines when it burns

Fraunhofer Lines: 1814 The English chemist William Hyde Wollaston was in

systematic study and careful measurement of the wavelength of these

43 Fraunhofer Lines: 1814 The English chemist William Hyde Wollaston was in 1802 the first person to note the appearance of a number of dark features in the solar spectrum. In 1814, Fraunhofer independently rediscovered the lines and began a systematic study and careful measurement of the wavelength of these features. In all, he mapped over 570 lines, and designated the principal features with the letters A through K, and weaker lines with other letters.

Kirkoff s Rules for Spectra: 1859 German physicist who developed the

Kirkoff Bunsen * Rule 1 : A hot and opaque solid, liquid or highly compressed

* Rule 2 : A hot, transparent gas produces an emission spectrum with bright

44 Kirkoff s Rules for Spectra: 1859 German physicist who developed the spectroscope and the science of emission spectroscopy with Bunsen. Kirkoff Bunsen * Rule 1 : A hot and opaque solid, liquid or highly compressed gas emits a continuous spectrum. * Rule 2 : A hot, transparent gas produces an emission spectrum with bright lines. * Rule 3 : If a continuous spectrum passes through a gas at a lower temperature, the transparent cooler gas generates dark absorption lines.

$spectrum, obtained with a diffraction grating, whose dispersion is linear, and replaced Kirchhoff's$ arbitrary scale by the wavelengths, expressed in the metric system, using a small unit (10-10 m) with which

arbitrary scale by the wavelengths, expressed in the metric system, using a small unit (10-10 m) with which

45 Anders Jonas Ångström 1869 Ångström measured the wavelengths on the four visible lines of the hydrogen spectrum, obtained with a diffraction grating, whose dispersion is linear, and replaced Kirchhoff's arbitrary scale by the wavelengths, expressed in the metric system, using a small unit (10-10 m) with which his name was to be associated. Line color red blue-green violet violet Wavelength Å Å Å Å

Balmer Series: 1885 Johann Balmer found an empirical equation that correctly predicted the four visible emission lines of hydrogen Johannes Robert Rydberg generalized it in 1888 for all transitions:

46 Balmer Series: 1885 Johann Balmer found an empirical equation that correctly predicted the four visible emission lines of hydrogen Johannes Robert Rydberg generalized it in 1888 for all transitions: 1 = R 1 1 λ 2 n H 2 2 R H is the Rydberg constant R H = x 10 7 m -1 n is an integer, n = 3, 4, 5, The spectral lines correspond to different values of n H α is red, λ = nm H β is green, λ = nm H γ is blue, λ = nm H δ is violet, λ = nm

47 Why a discrete spectrum? Why THIS spectrum?

48 Why this shape? Why the drop?

Sadi Carnot: Father of Thermo (1796 1832) 1824: A heat engine operating in an ideal, reversible cycle (now called a Carnot

49 Sadi Carnot: Father of Thermo ( ) 1824: A heat engine operating in an ideal, reversible cycle (now called a Carnot cycle) between two reservoirs is the most efficient engine possible. This sets an upper limit on the efficiencies of all other engines.

50 Kinetic Theory/Thermodynamics Gas Particles are in constant RANDOM motion Particles have different speeds Pressure : momentum transferred by particles colliding Average KE of each particle is ~ T Heat flows from hot to cold: Entropy

51 Young s Double Slit: Light is a Wave 1803 λl ybright = m ( m = 0, ± 1, ± 2 K ) d λl 1 ydark = m+ ( m= 0, ± 1, ± 2 K ) d 2

52 Oscillating Charges Produce Radio Waves: 1887 Heinrich Hertz I do not think that the wireless waves I have discovered will have any practical application." Frequency of EM wave is the same as the frequency of oscillation.

photo Zeeman took of the effect named for him Einstein

53 1896: Zeeman Effect The Zeeman Effect is the splitting of spectral lines when a magnetic field is applied. photo Zeeman took of the effect named for him Einstein visiting Pieter Zeeman in Amsterdam, with his friend Ehrenfest. (around 1920)

54 1860: E&M was Solved! (Vector Form)

55 James Clerk Maxwell 1860s Light is wave. The medium is the Ether. 1 8 c= = 3.0x10 m/ s με 0 o

56 Measure the Speed of the Ether Wind The Luminiferous Aether was imagined by physicists since Isaac Newton as the invisible "vapor" or "gas aether" filling the universe and hence as the carrier of heat and light.

57 Rotate arms to produce interference fringes and find different speeds of light.

58 Michelson-Morely Experiment 1887 The speed of light is independent of the motion and is always c. The speed of the Ether wind is zero. OR. Lorentz Contraction The apparatus shrinks by a factor : 1 v / c 2 2

59 Born 1879

60 Unsolved Mysteries of 1900 s that gave birth to Modern Physics Where is the ether? Is light particle or wave? What is matter made of? How and why do atoms radiate discrete spectra? Are nebulae within our galaxy or are they other galaxies? Is space & time finite? Infinite?

61 This is where our class begins.

Classical vs Modern Laws of Physics are deterministic. Space and time are absolute. Particles are Localized in Space and have mass and momentum.

62 Classical vs Modern Laws of Physics are deterministic. Space and time are absolute. Particles are Localized in Space and have mass and momentum. Waves are non-localized in space and do not have mass or momentum. Superposition: Two particles cannot occupy the same space at the same time! But Waves can! Waves add in space and show interference. Laws of Physics are statistical. Space and time are relative. The speed of light is absolute. Particles are wave-like Waves are particle-like

63 Modern Physics: Quantum & General Relativity

65 On the Electrodynamics of Moving Bodies 1905

66 A Problem with Electrodynamics The force on a moving charge depends on the Frame. Charge Rest Frame (moving with charge) Wire Rest Frame (moving with wire) F = 0 F = qvbsinθ Einstein realized this inconsistency and could have chosen either: Keep Maxwell's Laws of Electromagnetism, and abandon Galileo's Spacetime or, keep Galileo's Spacetime, and abandon the Maxwell Laws.

that from the rest frame of the charge outside the wire (or at rest in

67 Lorentz Contraction in Wire Moving charges in the wire cause a Lorentz contraction in the distance between the moving charges in the wire so that from the rest frame of the charge outside the wire (or at rest in the wire) the moving charges bunch up and thus give a net charge to the wire.

2 / r 2 From the rest frame of the charge, the wire is charged due to the Lorentz contraction

68 Eisntein Saves Maxwell! The force on a moving charge does NOT depend on the Frame. Charge Rest Frame (moving with charge) Wire Rest Frame (moving with wire) F = qvbsinθ F = kqq 1 2 / r 2 From the rest frame of the charge, the wire is charged due to the Lorentz contraction and thus it feels a Coulomb force. The forces in each frame are equal though they are due to different causes!

Postulates of Special Relativity 1905 1. The laws of physics are the same in all inertial reference frames. 2.

69 Postulates of Special Relativity The laws of physics are the same in all inertial reference frames. 2. The speed of light in a vacuum is constant in all inertial reference frames, independent of the relative motion of source and observer. 3. Months later E = mc 2

70 Special Theory: Inertial Reference Frames: Flat Spacetime No Acceleration-No Forces-No Gravity.

71 General Theory: Noninertial Reference Frames: Gravity Curved Spacetime

72 Newton s Principia in Galilean Relativity: Addition of Velocities Space and Time are ABSOLUTE! Velocities add: u= u +v

73 What if instead of a ball, it is a light wave? Do velocities add according to Galilean Relativity?

74 Time is Relative! Space is Relative! Only the SPEED OF LIGHT is Absolute!

Relative Velocity Two observers moving relative to each other generally do not agree on the outcome of an experiment For example, observers A and B below see different paths for

75 Relative Velocity Two observers moving relative to each other generally do not agree on the outcome of an experiment For example, observers A and B below see different paths for the ball and measure different velocities: Velocity of ball relative to observer B v = v + v bb ba AB Velocity of ball relative to observer A Velocity of A relative to observer B

76 Co-Linear Motion Just add or subtract the magnitudes of vectors! v = v + v PG PT TG Notice how the inner subscripts cancel!

77 2D Relative Velocity The boat can travel 2.50 m/s relative to the river. The river current flows at 1.00 m/s relative to the Earth. What is the total velocity of the boat relative to the Earth (shore = Earth)? v = v + v be br re 2 2 vbe = (2.5 m/ s) + (1 m/ s) = 2.69 m/ s 1 m/ s 1 1m/s θ = tan = m/s o 2.50 m/ s

78 The GalileanTransformations Consider two reference frames S and S'. The coordinate axes in S are x, y, z and those in S' are x', y', z'. Reference frame S' moves with velocity v relative to S along the x-axis. Equivalently, S moves with velocity v relative to S'. The Galilean transformations of position are: The Galilean transformations of velocity are:

79 Energy is Converted into Mass E = mc 2

80 Fission Heavy elements FISSION into lighter elements, releasing energy in the process by E = Δmc 2, where Δm is the difference in mass between the parent and products. ~ 25 MeV is released in this reaction Most of the Energy is released in the form of Kinetic Energy (heat).

81 Nuclear Weapons

82 Albert Einstein 1916 Mass warps space-time. The Field Equation:

83 Milky Way Galaxy At the turn of the 20 th century we did not know that there were other galaxies in the Universe!!! Orbital Speed of Solar System: 220 km/s Orbital Period: 225 Million Years

84 Cepheids Andromeda Galaxy V = H o d Hubble Observations made in the first to support extra galactic galaxies, and the Big Bang.

85 Space and Time were created in the Big Bang!

86 Evolution of Life in the Universe

88 What is the World Made of? Atoms?

89 Atomic Theory

91 If photons can be particles, then why can t electrons be waves? p hf = E/ c= = c debroglie Wavelength: h λ λ = e h p Electrons are STANDING WAVES in atomic orbitals.

92 Richard Feynman: Electron waves are probability waves in the ocean of uncertainty.

93 1926:Schrodinger s Equation Rewrite the SE in spherical coordinates. Solutions to it give the possible states of the electron. Solution: Probability = Ψ = (possibility) 2 2

94 The Quantum Gang

96 The Universe is made of Regular Matter: 5% Dark Matter: 25% Dark Energy: 70%

97 Dark Energy: The New Ether? Accelerating the Universe toward the Future

98 Future Evolution?

99 Quantum Entanglement Quantum Computing The Qubit At the heart of the realm of quantum computation is the qubit. The quantum bit, by analogy with the binary digit, the bit, used by everyday computers, the qubit is the quantum computer's unit of currency. Instead of being in a 1 or zero state, a qubit can be in a superposition of both states.

100 Quantum Teleportation??

101 Black Holes & Worm Holes

102 LISA Gravity Waves

103 Gravity Probe B Gravitational Frame Dragging Space-Time Twist

104 Parallel Universes Multiverse

105 String Theory

Quantum Entanglement Quantum Computing The Qubit At the

The quantum bit, by analogy with the binary digit, the

106 Quantum Entanglement Quantum Computing The Qubit At the heart of the realm of quantum computation is the qubit. The quantum bit, by analogy with the binary digit, the bit, used by everyday computers, the qubit is the quantum computer's unit of currency. Instead of being in a 1 or zero state, a qubit can be in a superposition of both states.

107 Quantum Teleportation Entangled photons are used to teleport other photons. Quantum Encryption

108 Casimir Effect: Proof of the Zero Point Energy of the Quantum Vacuum

109 Quantum Quackery?

The Final Frontier: Consciousness Each caged electron is a qubit in a nanoscale quantum dot. We have a billion billion of them enslaved by coherent near electromagnetic brain fields of low frequency.

110 The Final Frontier: Consciousness Each caged electron is a qubit in a nanoscale quantum dot. We have a billion billion of them enslaved by coherent near electromagnetic brain fields of low frequency. This forms a mind-brain hologram. There is direct back-reaction of the coherent phased array of single electron dipoles on their mental pilot landscape field. This generates our inner conscious experience. - Jack Sarfatti A Quantum Model of Consciousness

111

Welcome to Physics 43!

Welcome to Physics 43! Classical Mechanics! Study of the motion of objects and mechanical systems that are large relative to atoms and move at speeds much slower than the speed of light. You can t get